Only the UI editor has the flexibility to (possibly) implement such an idea.  It might work.  It might be a lot of work.

You'd essentially have to record the item ID of the item equipped in each inventory slot on the player character then somehow spawn that item into your clone's equipment slot.  This sounds difficult to me.

The other consideration is that spawning Human models that are wardrobeable (as opposed to pre-baked models like bandits) causes a lot of lag.

Yeah,I'm thinking i'm going to have to just spawn premade humanoid models. As even if I found a way to do it through the UI, I don't think there's a system to make "overlays" or w.e. to make the final unit have like, a purple hue or something.

Thanks guys.

I’m just an a idea man...

So, target need to have hitbox to be triggered by enemies. Limited life spam and be a visual mirror of main character.
I would consider:
-   Timed by event summon, or hurt box of solider from start of the game.
-   Life/hits can be calculated by level of player.
-   Mirror… you need to investigate the save file of character in play and duplicate it with counters for current character stats. So it would be woundable to attacks - more or less.
That might require you to create new tag system basted of data used by skills (that acts on your character level, stored somewhere), but with visuals.
That should be possible from what I saw in GUTS, but saved data loading requirement would require this mod to be single player or low mod ONLY.
You could use multiplayer dump data – or save file as I mentioned before – they should be static on all WindowsOS. Problem would consider tracing needed data. I do not know where multi dump is, but most of torchlight mods files can be edited in notepad so you can investigate it.